MashupException.Error: an error occurred during the pre-login handshake

[WhisperofCoding]

Hi guys,

I keep receiving an error while fetching data with a Dataflow Gen2. I am trying to get data through our Gateway (version 3000.178.9) but keep hitting the same error over and over. 

I tried 2 options through the gateway:

- Receiving data from a database on a local SQL server (autorization is correct)

- Receiving data from csv file on our network

Both options gave the same errors.

We also use Power BI through this same gateway without any problems. 

I used 'My workspace', but also created a new workspace, still the same problems.

Full error message:

Mashup Exception Error Couldn't refresh the entity because of an issue with the mashup document MashupException.Error: Microsoft SQL: A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.) Details: DataSourceKind = Lakehouse;DataSourcePath = Lakehouse;Message = A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.);ErrorCode = -2146232060;Number = 121;Class = 20 GatewayObjectId: xxxxxx

[Joe_Doe]

Hi! Has anyone found a solution to this problem? I'm having the same pre-login handshake error for all my Gen2 Dataflows. Gen1 Dataflows work fine. Whether I'm using a lakehouse or a warehouse as the destination, the same thing happens. I've tried many ways to fix this, but to no avail. I opened a support ticket, and they didn't offer any solution. Their response is that it's network glitches. :S

[SidJay]

If you're using a Gateway could you please verify that port 1433 is open.

More details:
On-premises data gateway considerations for data destinations in Dataflow Gen2 - Microsoft Fabric | ...

Thanks

[Joe_Doe]

Hi! Has anyone found a solution to this problem? I'm having the same pre-login handshake error for all my Gen2 Dataflows. Gen1 Dataflows work fine. Whether I'm using a lakehouse or a warehouse as the destination, the same thing happens. I've tried many ways to fix this, but to no avail. I opened a support ticket, and they didn't offer any solution. Their response is that it's network glitches. :S

[SidJay]

When a dataflow is bound to a Gateway, all the read and write operations are executed via the Gateway.

To transfer data from staging to a warehouse without using the Gateway, you would currently need a separate dataflow that is not bound to a Gateway.

Dataflows are either executed entirely in the Cloud or entirely on a Gateway. There isn't a blended mode.

Thanks

[SidJay]

Could you please confirm that the configuration that Miguel suggested earlier in the thread has been applied?

Configure proxy settings for the on-premises data gateway | Microsoft Learn

Additionally, Port 1433 needs to be opened. The documentation is being updated to include this.

Thanks

[motoray]

Am currently working with my IT folks to try and get that port opened. We'll see what they say.

I thought the whole point of the gateway is so you don't have to jump through these kinds of hoops--it's been pretty great up to now. And I still don't understand why the port needs to be opened if I'm getting data in the staging warehouse--at that point, isn't the next step just moving it from staging to the warehouse?

[miguel]

hey folks! Could you please read the article below and check if these proxy considerations have any impact on your scenarios?

Configure proxy settings for the on-premises data gateway | Microsoft Learn

[AnthonyGenovese]

I am having the same issue. It loads the data from on prem fine. You can see the data in the staging warehouse. However it doesn't write it to the Lakehouse correctly

[motoray]

Having the same issue here. Have tried everything I can think of--rebuilding the workspace and dataflows multiple times. I was able to load data from a Gen1 dataflow source into a Lakehouse, but can't get the onprem data to go from the staging lakehouse into the production lakehouse.

[WhisperofCoding]

I also tried the gateway port test, that all came out with status 'Success':

Overall Results : 32/32 tests succeeded.